<%-- Page Title--%> Sci-Tech <%-- End Page Title--%>

<%-- Volume Number --%> Vol 1 Num 148 <%-- End Volume Number --%>

April 2, 2004

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Virtual Reality Conquers Sense Of taste

Food companies cooking up a novel product will soon be able to check how elderly people will fare when they try to chew on it, thanks to a device that mimics the taste and "mouthfeel" of food.

Already, virtual reality devices have been built that try to simulate experiences for four of our five senses -- vision, hearing, touch and smell. But the complexity of the sense of taste has made it difficult for computers to conquer.

Taste combines the feel of food in the mouth with chemical and even auditory cues. Hiroo Iwata of the University of Tsukuba in Japan and colleagues call it the "last frontier of virtual reality".

But it is a frontier they have now crossed. "The food simulator is the first media technology that is put into the mouth," says Iwata.

Before simulating a foodstuff, the team first measures and records various phenomena associated with chewing it. One such parameter is the force required to bite through a piece of the food. A thin-film force sensor placed in a subject's mouth records these forces. Biological sensors made of lipid and polymer membranes record the major chemical constituents of the food's taste. A microphone records the audible vibrations produced in the jawbone while chewing. These parameters serve as inputs to the food simulator. The mechanical part of the simulator that is inserted into the mouth has cloth and rubber covers, mainly for sanitary reasons, and is intended to resist the user's bite in a similar way to the real foodstuff. When someone chews the device, a sensor registers the force of the bite and a motor provides appropriate resistance.

To augment the experience, a thin tube squirts a mixture of flavourings onto the tongue. The chemicals stimulate the five basic taste sensations: sweet, sour, bitter, salty and umami - the taste of monosodium glutamate. Meanwhile, a tiny speaker plays back the sound of a chewing jawbone in the user's ear.

Iwata says that his team has successfully simulated many foods, including cheese, crackers, confectionery and Japanese snacks. One remaining step still to be tackled is to use a vaporiser to deliver appropriate smells to the nose. The researchers say their device is perfect for people designing new foods, and may even allow young designers to experience the difficulty older people may face in chewing food.

The technology can also be entertaining -- for the researcher at the controls, at least. By suddenly changing the properties of a food in mid-chew -- from a cracker to a jelly, say -- the result is uniquely funny, says Iwata.

Vibrating pedal says
'Ease off gasí

A vibrating accelerator pedal that tells motorists when to slow down could save them a substantial amount of money in fuel bills. Most drivers waste fuel by braking for traffic lights or other obstacles only at the last minute, but expert drivers see that they will need to slow down and take their foot off the throttle much sooner.

The vibrating pedal is part of a prototype system that mimics this approach by monitoring traffic, speed restrictions, junctions coming up and so on, and then telling drivers to ease off the gas.

The principle is simple. If your car is travelling at, say, 80 kilometres per hour, it burns more fuel per kilometre than if it is travelling at 50 kph. So if you know you have to slow down from 80 to 50 kph in perhaps 300 metres, you may as well decelerate straight away and drop to the lower fuel-consumption rate.

The vibrating alert system, from DaimlerChrysler -- which owns Mercedes, Jeep and Smart, among others -- is designed to help you save fuel this way. Trials with 70 volunteer drivers indicate an average reduction of 11 per cent.

The device is computerised, and combines measurements from several sources to help it judge when the car will need to start slowing down. It uses GPS to work out where it is on the road network, but its map contains far more information than those used in most satellite navigation systems for cars: it includes speed limits, gradients and road curve radii.

The S-Class Mercedes automatic that has been fitted with the prototype also has vehicle-detection radar so the driver can tell when they are getting too close to cars in front.

A PC mounted in the car assimilates these measurements and predicts whether the car will need to decelerate, perhaps to take a sharp bend. It calculates the optimum moment for the driver's foot to leave the throttle and sends a signal to a small actuator fixed under the pedal, which lightly vibrates a small piston against the underside of the pedal rubber.

"It simply alerts the motorist to the situation and gives him or her a choice about what to do next." says Klaus-Peter Kuhn of DaimlerChrysler's human-machine interaction group.

Vibration alert was chosen because drivers react faster to it than they do to dashboard lights. In DaimlerChrysler's tests in Stuttgart, Germany, drivers took 2.0 seconds to react to a light, but only 0.3 seconds to respond to a vibration.

There is one hitch that might make it hard to sell the technology. The fuel-saving benefits would not be shown on the official fuel consumption figures for any car it was fitted to, since efficiency figures are obtained from simple tests at different speeds on a rolling road -- they do not take into account the effects of corners, traffic or hills.

Unless the tests are changed, says Kuhn, the company would not be able to advertise the fuel savings, and there would be less incentive to fit cars with the system. The firm is now hoping for an overhaul of the tests to make this possible.

Butter that not only spreads easily when cold, but also contains a healthier balance of fats has been developed by researchers tinkering with the diets of cows.

"To be able to lift it out of the fridge and spread it is brilliant, and knowing I'm doing myself less harm is even better," says Anna Fearon, who led the team which developed the spread at the University of Belfast in Northern Ireland. "It does taste like real butter too," she adds.

The scientists altered the fat profile of the milk from which the butter was made by adding rapeseed oil to the cow's fodder. Fearon says that it would also be possible to make cheese, ice cream and other dairy products from the "healthier" milk.

Cows consuming 600 grams of rapeseed (canola) oil every day produced milk containing 26 per cent less palmitic acid, the "bad" saturated fat which is thought to clog up arteries. At the same time, beneficial "unsaturated" fats like those in some margarines went up substantially. Oleic acid, abundant in olive oil, rose by 35 per cent.

These changes had another benefit - making the butter spreadable at lower temperatures. Palmitic acid melts at 62°C, whereas oleic acid melts at just 16°C, and is soft at fridge temperatures of 4°C.

Fearon says that altering the fat composition was not simple, as pure rapeseed oil can harm vital bacteria in the rumen, the cow's forestomach where grass is pre-digested.

To avoid this, Fearon's team added the oil in the form of raw seeds. These pass straight through the rumen without disturbing the bacteria, before being digested later. None of the cows in the trials suffered any adverse effects, she says. The team also showed the more rapeseed they gave the cows, the better the balance of fats.

Fearon's team reported its findings in a journal on Monday, the first disclosure of the science behind the "Pure Butter" product made by Dromona Quality Foods of Cullybackey, County Antrim. It is already on sale in Northern Ireland and at Marks and Spencer outlets in Britain.

"For butter eaters like myself, improving the fatty acid profile is beneficial," says Jackie Brown, senior research scientist at the Institute of Food Research in Norwich, Norfolk. "But it still has more saturated fat than some of the margarines."

Also, some margarines are richer in the polyunsaturated fats which decrease the amount of artery-clogging cholesterol in blood. "Although this butter is greatly improved and contains mono-unsaturated fats, it still is not the healthiest option for those with high blood cholesterol," says Brown.


Source: Newscientist.com


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